Parasite on farmed salmon threatens wild species: study

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Pink salmon (Courtesy: Alexandra Morton)

A microscopic pest could cause big problems for British Columbia's salmon farming industry, a new study suggests.

In research published on Wednesday, biologists concluded sea lice populations are exploding off the province's coast, putting wild salmon stocks in jeopardy.

Study author Martin Krkosek of the University of Alberta said his research shows sea lice from salmon farms are a threat to young, wild salmon that haven't developed an immunity to the parasites.

"The two major conclusions are that lice are transmitted from farm salmon to wild salmon and that this occurs at rates that are much greater than most of us believe," said Krkosek, who is writing his doctoral thesis on the problem.

The peer-reviewed study, which appears in the London-based journal Proceedings of the Royal Society B, is already drawing fire from other researchers.

"That's totally irresponsible," said Scott McKinley, chair of Canadian aquaculture and environmental research at the University of British Columbia. "You can't draw a link when you only have half the data. There are deficiencies in their model and in their sampling."

McKinley said the report is too flawed to draw any conclusions about how salmon farming affects wild salmon stocks.

Ransom Myers, a marine biology professor at Dalhousie University in Halifax, disagreed with McKinley's interpretation. Myers called the study on 5,514 migrating juvenile pink and chum salmon "a very thorough analysis."

The David Suzuki Foundation, which funded the research, said the results show the aquaculture industry needs to be reformed.

"The evidence just keeps mounting," said Jay Richin, a spokesperson for the environmentalists. "In Europe, they have accepted it for years that there is a link between these farms and the sea lice."

While the latest study won't lead to a consensus among scientists, everyone interviewed agreed more research is needed.

Until now, the federal government has concluded salmon farms effectively control sea lice. Given concerns over dwindling numbers of young native salmon off northern Vancouver Island, the government plans to conduct more research.